The present invention relates to a plastic closure cap made by injection molding for a fuel tank of a motor vehicle, the cap having at least one fuel line passing through it and contact pins which also pass through it.
Such a closure cap is frequently use in modern motor vehicles when an electric fuel pump is arranged in the fuel tank, and it is therefore known. In that case, the fuel lines which extend out of the fuel tank preferably pass through the closure cap. Electric wires leading to the fuel pump are contacted with the contact pins which are incorporated in the closure cap. Plastic has proven particularly suitable as material for the closure cap since it can be easily worked by injection molding and therefore is of very favorable price in mass production. The contact pins can be simply pressed into such a plastic, or the plastic injected around them.
Furthermore, a closure cap made by plastic injection molding has a high resistance to impact and is of a very good vibrational behavior. Such a closure cap offers a high degree of acoustic dampening and good protection against the fuel flowing out of the fuel container, for instance upon an accident.
A closure cap produced by plastic injection molding has the disadvantage of low material strength at high temperatures. Particularly in modern motor vehicles with diesel engine, temperatures of up to 120.degree. C. and pressures up to 4 bar prevail in the fuel lines, so that the mechanical strength of the closure cap is exceeded in the region of the fuel line. One could consider making the closure cap of a material having a higher resistance to temperature. Such closure caps would then, however, be expensive to manufacture or too brittle to prevent the escape of the fuel from the fuel tank in the event of an accident. Furthermore, no heat-resistant plastic is known into which the contact pins can be worked as easily as in the case of the known plastic for injection molding. In the case of a closure cap consisting of a metallic material there is furthermore the problem of insulating the contact pins.